266 research outputs found
Trends and topics: Characterizing echo chambers’ topological stability and in-group attitudes
No full textNowadays, online debates focusing on a wide spectrum of topics are often characterized by clashes of polarized communities, each fiercely supporting a specific stance. Such debates are sometimes fueled by the presence of echo chambers, insulated systems whose users’ opinions are exacerbated due to the effect of repetition and by the active exclusion of opposite views. This paper offers a framework to explore how echo chambers evolve through time, considering their users’ interaction patterns and the content/attitude they convey while addressing specific controversial issues. The framework is then tested on three Reddit case studies focused on sociopolitical issues (gun control, American politics, and minority discrimination) during the first two years and a half of Donald Trump’s presidency and on an X/Twitter dataset involving BLM discussion tied to the EURO 2020 football championship. Analytical results unveil that polarized users will likely keep their affiliation to echo chambers in time. Moreover, we observed that the attitudes conveyed by Reddit users who joined risky epistemic enclaves are characterized by a slight inclination toward a more negative or neutral attitude when discussing particularly sensitive issues (e.g., fascism, school shootings, or police violence) while X/Twitter ones often tend to express more positive feelings w.r.t. those involved into less polarized communities
Bots of a feather: mixing biases in LLMs’ opinion dynamics
No full textThe rapid integration of Large Language Models (LLMs) into everyday applications raises critical questions about their group in- teractions, consensus formation, and potential to mimic human-like be- havior. Although initial research has explored the evolution of opinions within LLM populations, these efforts often rely on simplistic network assumptions, such as uniform connections among agents, thereby over- looking the influence of more realistic network topologies. This paper introduces a framework for examining opinion dynamics among LLM agents within various network structures. We perform several multi- model simulations on network topologies with known locally assorta- tive/disassortative mixing patterns. We find that convergence is quicker in mostly-disassortative networks compared to networks with no mixing biases. However, the joint effect of assortative and disassortative patterns leads to slower/no convergence
Confined Water Cluster Formation in Water Harvesting by Metal–Organic Frameworks: CAU-10-H versus CAU-10-CH<sub>3</sub>
No full textSeveral metal–organic frameworks (MOFs) excel in harvesting water from the air or as heat pumps as they show a steep increase in water uptake at 10–30 % relative humidity (RH%). A precise understanding of which structural characteristics govern such behavior is lacking. Herein, CAU-10-H and CAU-10-CH3 are studied with -H, -CH3 corresponding to the functions grafted to the organic linker. CAU-10-H shows a steep water uptake ≈18 RH% of interest for water harvesting, yet the subtle replacement of -H by -CH3 in the organic linker drastically changes the water adsorption behavior to less steep water uptake at much higher humidity values. The materials’ structural deformation and water ordering during adsorption with in situ sum-frequency generation, in situ X-ray diffraction, and molecular simulations are unraveled. In CAU-10-H, an energetically favorable water cluster is formed in the hydrophobic pore, tethered via H-bonds to the framework μ-OH groups, while for CAU-10-CH3, such a favorable cluster cannot form. By relating the findings to the features of water adsorption isotherms of a series of MOFs, it is concluded that favorable water adsorption occurs when sites of intermediate hydrophilicity are present in a hydrophobic structure, and the formation of energetically favorable water clusters is possible.ChemE/Catalysis Engineerin
Post-combustion CO2 capture of methyl and nitro mixed-linker CAU-10
No full textMethyl- and nitro-group-co-functionalized CAU-10, namely CAU-10-CH3-NO2, was synthesized and compared with mono-functionalized CAU-10 derivatives, CAU-10-CH3 and CAU-10-NO2, as a CO2 adsorbent. In this study, we report that methyl and/or nitro groups could increase CO2 performance compared to that of bare CAU-10. It is supposed that the hydrophobic character of the methyl group might support selective CO2 uptake in humid conditions. Breakthrough experiments demonstrate that CAU-10-CH3-NO2, which is more hydrophobic than CAU-10-NO2, reduced the degradation of adsorption performance under dry conditions. CAU-10-CH3-NO2 was considered a candidate suitable for an actual post-combustion CO2 adsorption process. Graphical abstract: [Figure not available: see fulltext.]. © 2023, The Author(s), under exclusive licence to The Materials Research Society.11Nsciescopu
Dr. Abi Adegboye Awomolo, CAU, August 2011
No full textThis video is a conversation with Dr. Abi Adegboye Awomolo. Dr. Abi Awomolo talks about her book, "Wanna B Prez?: 10 Life Strategies From President Barack Obama's Journey to the White House". Ola Ijimayowa, AUC Woodruff Library, is the interviewer
Dr. F.S.J. Ledgister, CAU, August 2011
No full textThis video is a conversation with Dr. F.S.J. Ledgister. Dr. Ledgister talks about his book, "Only West Indians: Creole Nationalism in the British West Indies". Ola Ijimayowa, AUC Woodruff Library, is the interviewer
Dr. Lin Sun, CAU, March 2013
No full textThis video is a conversation with Dr. Lin Sun. Dr. Sun talks about an exhibit at the Woodruff Library titled "At The Boundary." Jordan Moore, AUC Woodruff Library, is the interviewer
Water adsorption behaviour of CAU-10-H: a thorough investigation of its structure–property relationships
No full textAluminium isophthalate CAU-10-H [Al(OH)(benzene-1,3-dicarboxylate)]·nH2O exhibits water adsorption characteristics which make it a promising adsorbent for application in heat-exchange processes. Herein we prepared a stable coating of this MOF and evaluated its long-term stability under closed-cycle conditions for 10 000 water adsorption and desorption cycles, which are typical lifetimes for adsorption heat storage (AHS) applications. No degradation of the adsorption capacity could be observed which makes CAU-10-H the most stable MOF under these humid cycling conditions reported until now. Moreover, thermophysical properties like thermal conductivity and heat of adsorption were directly measured. In order to identify the structural features associated with the adsorption behaviour, the structural differences between the dry and the water loaded CAU-10-H were studied by Rietveld refinements and second harmonic generation (SHG) microscopy. The observed transition of space group symmetry from I41 to I41/amd between the humid and dry forms is induced by the adsorption/desorption of water into/out of the MOF channels. This originates from a torsional motion around the C–C bond between the carboxylate groups and the aromatic ring in half of the linker molecules. These observations are in excellent agreement with molecular dynamics simulations which confirm the energetic benefit of this transition
Project Hue: Report and field study on the water related problems and solutions in and around the Cau Hai lagoon and the Tu Hien inlet, Vietnam
No full textThe Tam Giang-Cau Hai lagoon system, lying in the Thua Thien-Hue province in central Vietnam, is affected by a tropical monsoon climate. This among others is the reason the Cau Hai Lagoon area has a long history of floods and other water related problems. Inhabitants are very dependent on the lagoon, as the main sources of income of people living in the region are fishing, agri- and aquaculture. The project goal has been formulated as follows: Finding an economic as well as technical feasible solution to reduce the water related problems, specifically navigability, salt intrusion and floods, in and around the Cau Hai Lagoon and the Tu Hien inlet and thereby improving the economic development of the region. Concerning flood risk, navigability and salt intrusion the inlet stability and size are important aspects. Using an echo sounder the bathymetry of the inlet has been measured. The measured size of the inlet was one of the input parameters for the hydraulic model that has been set up. This basic model of the Cau Hai basin system was made to test some alternative solutions for the Tu Hien inlet. The different solutions were simulated for five different scenarios. These scenarios include average dry season conditions, average wet season conditions and multiple extreme events. The output of the model for the different alternatives was used to rate the alternatives for a couple of criteria in a Multi Criteria Analysis. Other criteria of the MCA are qualitatively rated. The most promising alternative proved to be the one including a jetty at the northern side of the Tu Hien inlet in combination with a bank protection at the other side. In this way a large part of the littoral drift is blocked, enlarging the equilibrium cross-section of the inlet. This in turn results in a better flood evacuation capacity, navigability and water quality in the lagoon. For both mentioned elements a preliminary technical design is made, resulting in the stone class needed for the armour layers, dimensions of the toe and characteristics of the filter.Hydraulic EngineeringCivil Engineering and Geoscience
Manufacture of dense CAU-10-H coatings for application in adsorption driven heat pumps: Optimization and characterization
No full textCAU-10-H displays a highly suitable step-wise water adsorption behaviour for application in adsorption driven heat pumps and chillers. For actual application, manufacturing of coatings of this material on thermally conductive surfaces is highly desired. Direct, single-step, crystallization of CAU-10-H on either metallic or anodized aluminium yields a significant amount of by-product(s) and an inhomogeneous substrate coverage. Although adequate pretreatment of the substrates before crystallization improves the quality of obtained coatings, significant improvements are achieved only when crystal nucleation and growth are separated. More specifically, application of a reactive seeding approach with anodized aluminium leads to full coverage of the substrate surface, high MOF loading and high purity of the crystalline phase, homogeneous layer thickness, narrow crystal size distribution, and good stability in repeated water adsorption–desorption cycles.Process and EnergyMechanical Maritime and Materials Engineerin
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